In order to afford maximum protection to vehicular traffic as well as to pedestrians at railroad and highway grade crossings, it is essential to provide suitable warning signals, both visual and audible, when a train is approaching the crossing. In addition to the flashing lights and clanging bell, a dangerous and/or heavily traveled intersection should be supplemented by a highway crossing gate assembly for more adaptly protecting the general public and, particularly, motorists and passengers. In the past, grade crossing gates were initially expensive to install and were subsequently costly to maintain due to their heavy and bulky construction. Prior crossing gate installations utilizing wooden or fiberglass arms normally required two or more maintainers to replace the heavy and cumbersome arm when it was run through and/or damaged by a motor vehicle. When the heavy wooden gate arm is broken, the counterweights unbalance the supporting arms and brackets and cause the output shaft to rapidly rotate to its vertical clear position. Previous types of highway crossing gate mechanisms required ancillary means, such as, a centrifugal coupler or dampening brake, in order to prevent the gate arm counterweights from dropping suddenly and causing damage to the operating mechanism in the event that the gate arm was broken while it was in its lowered or traffic blocking position. Further, it will be appreciated that when the gate arm is broken, the counterweights cause the mechanism to rotate toward its vertical position so that the support arms and bracket are pointed skyward so that the gate receiving end rotates out of the normal reach of the maintainer and it becomes extremely difficult, if not impossible, to replace the arm in this position. In many instances, the counterweights, which could amount to as much as 400 pounds or more, had to be removed from the gate supports so that the mechanism could be rotated to its horizontal position before the broken wooden gate could be replaced and placed in working order. A further disadvantage of previous highway crossing gates involves the awkward manner in measuring the dropping and lifting torques on the gate arm. It was common practice, after the gate arm is mounted to the gate supports, for a maintainer to employ a fish or spring scale and attach it to a given point on the gate arm. When the gate arm is in its lowered or traffic obstructing position, the maintainer would hold the free end of the fish scale and would pull vertically upward until the gate arm would begin to lift. He would then note the reading on the fish scale and multiply it by the moment arm to obtain the torque in footpounds. In order to obtain the free moving downward torque, when the gate arm is in its upper or clear position, the maintainer first has to set up a ladder against the supporting mast, and after climbing the ladder, he would attach the fish scale to a given point along the length of the gate arm. While the free end of the fish scale would be held by one maintainer, another maintainer would deenergize the hold clear device so that the gate arm was free to move toward its zero or horizontal position under the force of gravity. The downward movement of the gate arm exerts a force on the fish scale which when multiplied by the movement arm signifies the torque in foot-pounds. It will be appreciated that the lifting and downward torques could be varied by shifting the counterweights or by increasing or descreasing their mass until the desired torque was obtained by trial and error.